When you connect OnePlus Two to PC, it may or may not recognize the device. If PC fails to recognize, you should install OnePlus Two USB drivers. Installing these drivers lets you configure ADB and fastboot setup easily. You need not manually download and install drivers from Device manager.
To unlock Oneplus Two bootloader, to root it and to flash custom firmware we need it connected to PC. So, if you wish to follow up this simple process, download the setup file from the below link
OnePlus Two Drivers (Only for Windows Operating System)
Double click the setup file to initiate and install it manually. Now restart the PC and connect OnePlus Two using a USB cable. It should be recognized now.